Compound, material for forming underlayer film for lithography, underlayer film for lithography and pattern forming method

ABSTRACT

The material for forming an underlayer film for lithography of the present invention contains a compound having a structure represented by the following general formula (1). 
                         
(in formula (1), each X independently represents an oxygen atom or a sulfur atom, R 1  represents a single bond or a 2n-valent hydrocarbon group having 1 to 30 carbon atoms, the hydrocarbon group may have a cyclic hydrocarbon group, a double bond, a hetero atom or an aromatic group having 6 to 30 carbon atoms, R 2  represents a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or a hydroxyl group, m is an integer of 0 to 3, n is an integer of 1 to 4, p is 0 or 1, and q is an integer of 1 to 100.).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national phase application filed under 35U.S.C. §371 of International Application PCT/JP2014/052530, filed onFeb. 4, 2014, designating the United States, which claims priority fromJapanese Application Number 2013-023809, filed Feb. 8, 2013, which arehereby incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a compound having a specific structure,a material for forming an underlayer film for lithography, containingthe compound, and a forming method of a pattern by using the materialfor forming an underlayer film for lithography.

BACKGROUND ART

Semiconductor devices are manufactured through microfabrication bylithography using a photoresist material, but are required to be madefiner by a pattern rule in accordance with the increase in integrationdegree and the increase in speed of LSI in recent years. In lithographyusing exposure to light, which is used as a general-purpose technique atpresent, the resolution is now approaching the intrinsic limitationassociated with the wavelength of the light source.

A light source for lithography, for use in forming a resist pattern, hasa shorter wavelength from a KrF excimer laser (248 nm) to an ArF excimerlaser (193 nm). As the resist pattern is made finer and finer, however,there arise a problem of resolution or a problem of collapse of theresist pattern after development, and therefore there is demanded formaking a resist film thinner. If the resist film is merely made thinnerin response to such a demand, it is difficult to achieve a resistpattern having a film thickness sufficient for processing a substrate.Accordingly, there is increasingly required a process in which not onlythe resist pattern but also a resist underlayer film is prepared betweena resist and a semiconductor substrate to be processed and the resistunderlayer film is allowed to have a function as a mask at the time ofprocessing the substrate.

Currently, as the resist underlayer film for such a process, variousones are known. Examples can include a resist underlayer film forlithography, having a selection ratio of dry etching rate close to theresist, unlike a conventional resist underlayer film having a highetching rate. As a material for forming such a resist underlayer filmfor lithography, there has been proposed a material for forming anunderlayer film for multilayer resist process, containing a resincomponent having at least a substituent which releases a terminal groupto form a sulfonic acid residue when a predetermined energy is applied,and a solvent (see, for example, Japanese Patent Laid-Open No.2004-177668). In addition, examples can also include a resist underlayerfilm for lithography, having a smaller selection ratio of dry etchingrate than the resist. As a material for forming such a resist underlayerfilm for lithography, there has been proposed a resist underlayer filmmaterial including a polymer having a specified repeating unit (see, forexample, Japanese Patent Laid-Open No. 2004-271838). Furthermore,examples can also include a resist underlayer film for lithography,having a smaller selection ratio of dry etching rate than thesemiconductor substrate. As a material for forming such a resistunderlayer film for lithography, there has been proposed a resistunderlayer film material including a polymer formed by co-polymerizing arepeating unit of acenaphthylene, and a substituted or non-substitutedrepeating unit having a hydroxy group (see, for example, Japanese PatentLaid-Open No. 2005-250434).

On the other hand, as a material for allowing such a resist underlayerfilm to have a high etching resistance, an amorphous carbon underlayerfilm is well known, which is formed by CVD using methane gas, ethanegas, acetylene gas, or the like as a raw material. However, there isdemanded, in terms of process, a resist underlayer film material thatcan form a resist underlayer film in a wet process such as a spincoating method or screen printing.

In addition, as a material that is excellent in optical characteristicsand etching resistance and that is capable of being dissolved in asolvent and being applied to a wet process, the present inventors haveproposed a composition for forming an underlayer film for lithography,which contains a naphthalene formaldehyde polymer including a specifiedconstituent unit, and an organic solvent (see, for example,International Publication No. WO 2009/072465 and InternationalPublication No. WO 2011/034062).

Meanwhile, with respect to a forming method of an intermediate layer foruse in forming a resist underlayer film in a three-layer process, forexample, known are a forming method of a silicon nitride film (see, forexample, Japanese Patent Laid-Open No. 2002-334869), and a CVD formingmethod of a silicon nitride film (see, for example, InternationalPublication No. WO 2004/066377). In addition, as an intermediate layermaterial for a three-layer process, known is a material containing asilsesquioxane-based silicon compound (see, for example, Japanese PatentLaid-Open No. 2007-226170 and Japanese Patent Laid-Open No.2007-226204).

SUMMARY OF INVENTION

As described above, many materials for forming an underlayer film forlithography have been conventionally proposed, but there are no onesthat not only have such a high solvent solubility as to be able to beapplied to a wet process such as a spin coating method or screenprinting, but also simultaneously satisfy heat resistance and etchingresistance at a high level, and thus a new material is demanded to bedeveloped.

The present invention has been made in view of the above problem. Thatis, an object of the present invention is to provide a compound, amaterial for forming an underlayer film for lithography, and a formingmethod of a pattern by using the material, which can be applied to a wetprocess and which are useful for forming a photoresist underlayer filmexcellent in heat resistance and etching resistance.

The present inventors have intensively studied to solve the aboveproblem, and as a result, have found that the above problem can besolved by using a compound having a specified structure, thereby leadingto the completion of the present invention.

That is, the present invention provides the following [1] to [19].

[1] A material for forming an underlayer film for lithography,comprising a compound having a structure represented by the followinggeneral formula (1).

(in formula (1), each X independently represents an oxygen atom or asulfur atom, R¹ represents a single bond or a 2n-valent hydrocarbongroup having 1 to 30 carbon atoms, the hydrocarbon group may have acyclic hydrocarbon group, a double bond, a hetero atom or an aromaticgroup having 6 to 30 carbon atoms, R² represents a linear, branched orcyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or ahydroxyl group, m is an integer of 0 to 3, n is an integer of 1 to 4, pis 0 or 1, and q is an integer of 1 to 100.)[2] The material for forming the underlayer film for lithographyaccording to [1], wherein the compound having a structure represented bythe general formula (1) comprises a compound represented by thefollowing general formula (1a).

(in formula (1a), X, R¹, R², m, n, p, and q are the same as defined inthe formula (1).)[3] The material for forming the underlayer film for lithographyaccording to [2], wherein the compound represented by the generalformula (1a) comprises a compound represented by the following generalformula (1b).

(in formula (1b), X, R¹, n, p, and q are the same as defined in theformula (1), each R⁴ independently represents a linear, branched orcyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or ahydroxyl group, and each m⁴ is independently an integer of 0 to 2.)[4] The material for forming the underlayer film for lithographyaccording to [3], wherein the compound represented by the generalformula (1b) comprises a compound represented by the following generalformula (1c).

(in formula (1c), R¹, n, and q are the same as defined in the formula(1), and R⁴ and m⁴ are the same as defined in the formula (1b).)[5] The material for forming the underlayer film for lithographyaccording to [4], wherein the compound represented by the generalformula (1c) comprises a compound represented by the following generalformula (1d).

(in formula (1d), R¹ represents a single bond or a divalent hydrocarbongroup having 1 to 30 carbon atoms, the hydrocarbon group may have acyclic hydrocarbon group, a double bond, a hetero atom or an aromaticgroup having 6 to 30 carbon atoms, q is the same as defined in theformula (1), and R⁴ and m⁴ are the same as defined in the formula (1b).)[6] The material for forming the underlayer film for lithographyaccording to [5], wherein the compound represented by the generalformula (1d) comprises a compound represented by the following generalformula (1e).

(in formula (1e), R¹ is the same as defined in the formula (1d), q isthe same as defined in the formula (1), and R⁴ and m⁴ are the same asdefined in the formula (1b).)[7] The material for forming the underlayer film for lithographyaccording to [6], wherein the compound represented by the generalformula (1e) comprises a compound represented by the following generalformula (1f) or (1g).

(in formula (1f) and formula (1g), R¹ is the same as defined in theformula (1d), q is the same as defined in the formula (1), and R⁴ and m⁴are the same as defined in the formula (1b).)[8] The material for forming the underlayer film for lithographyaccording to [7], wherein the compound represented by the generalformula (1f) comprises a compound represented by the following generalformula (1h) or (1i).

(in formula (1h) and formula (1i), R¹ is the same as defined in theformula (1d), and R⁴ and m⁴ are the same as defined in the formula(1b).)[9] The material for forming the underlayer film for lithographyaccording to [7], wherein the compound represented by the generalformula (1g) comprises a compound represented by the following generalformula (1j) or (1k).

(in formula (1j) and formula (1k), R¹ is the same as defined in theformula (1d), and R⁴ and m⁴ are the same as defined in the formula(1b).)[10] The material for forming the underlayer film for lithographyaccording to [8], wherein the compound represented by the generalformula (1h) comprises a compound represented by the following formula(BisN-1).

[11] The material for forming the underlayer film for lithographyaccording to [8], wherein the compound represented by the generalformula (1i) comprises a compound represented by the following formula(BisN-2).

[12] The material for forming the underlayer film for lithographyaccording to any of [1] to [11], further comprising an organic solvent.[13] The material for forming the underlayer film for lithographyaccording to any of [1] to [12], further comprising an acid generatingagent.[14] The material for forming the underlayer film for lithographyaccording to any of [1] to [13], further comprising a crosslinkingagent.[15] An underlayer film for lithography, formed from the material forforming the underlayer film for lithography according to any of [11] to[14].[16] A forming method of a pattern, comprising:

step (A-1) of forming an underlayer film on a substrate by using thematerial for forming the underlayer film according to any of [1] to[14];

step (A-2) of forming at least one photoresist layer on the underlayerfilm; and

step (A-3) of irradiating a predetermined region of the photoresistlayer with radiation followed by developing with an alkali, after step(A-2).

[17] A forming method of a pattern, comprising:

step (B-1) of forming an underlayer film on a substrate by using thematerial for forming the underlayer film according to any of [1] to[14];

step (B-2) of forming an intermediate layer film on the underlayer filmby using a silicon atom-containing resist intermediate layer filmmaterial;

step (B-3) of forming at least one photoresist layer on the intermediatelayer film;

step (B-4) of irradiating a predetermined region of the photoresistlayer with radiation followed by developing with an alkali to form aresist pattern, after step (B-3); and

step (B-5) of etching the intermediate layer film while the resistpattern functions as a mask, etching the underlayer film while theobtained intermediate layer film pattern functions as an etching maskand etching the substrate while the obtained underlayer film patternfunctions as an etching mask to form a pattern on the substrate, afterstep (B-4).

[18] A compound represented by the following formula (BisN-1).

[19] A compound represented by the following formula (BisN-2).

According to the present invention, it is possible to provide a materialfor forming an underlayer film for lithography, which can be applied toa wet process and which is useful for forming a photoresist underlayerfilm excellent in heat resistance and etching resistance.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention (hereinafter, alsosimply designated as “the present embodiment”) will be described. It isto be noted that the following embodiments are illustrative fordescribing the present invention, and the present invention is notlimited only to the embodiments.

(Material for Forming Underlayer Film for Lithography)

A compound of the present embodiment is represented by the followinggeneral formula (1). The compound of the present embodiment has such astructure, and therefore has a high heat resistance, a relatively highcarbon concentration, a relatively low oxygen concentration, and also ahigh solvent solubility. Moreover, a material for forming an underlayerfilm for lithography of the present embodiment contains the compound ofthe present embodiment. The material for forming an underlayer film forlithography of the present embodiment has such a structure, andtherefore can be applied to a wet process, and is excellent in heatresistance and etching resistance. Furthermore, the material for formingan underlayer film for lithography of the present embodiment is formedusing the above compound or resin having a specific structure, andtherefore the material can be used to form an underlayer film whosedegradation is suppressed at high-temperature baking and which is alsoexcellent in etching resistance to oxygen plasma etching or the like.Moreover, the material for forming an underlayer film for lithography ofthe present embodiment is also excellent in adhesiveness with a resistlayer, and therefore can provide an excellent resist pattern.

In the general formula (1), each X independently represents an oxygenatom or a sulfur atom, R¹ represents a single bond or a 2n-valenthydrocarbon group having 1 to 30 carbon atoms, the hydrocarbon group mayhave a cyclic hydrocarbon group, a double bond, a hetero atom or anaromatic group having 6 to 30 carbon atoms, each R² independentlyrepresents a linear, branched or cyclic alkyl group having 1 to 10carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkenylgroup having 2 to 10 carbon atoms, or a hydroxyl group, m is an integerof 0 to 3, n is an integer of 1 to 4, p is 0 or 1, and q is an integerof 1 to 100.

Herein, the 2n-valent hydrocarbon group represents an alkylene grouphaving 1 to 30 carbon atoms when n=1, an alkanetetrayl group having 1 to30 carbon atoms when n=2, an alkanehexayl group having 2 to 30 carbonatoms when n=3, and an alkaneoctayl group having 3 to 30 carbon atomswhen n=4. Examples of the 2n-valent hydrocarbon group include thosehaving a linear, branched or cyclic structure.

In addition, the 2n-valent hydrocarbon group may have a cyclichydrocarbon group, a double bond, a hetero atom, or an aromatic grouphaving 6 to 30 carbon atoms. Herein, the cyclic hydrocarbon group alsoincludes a bridged cyclic hydrocarbon group.

The compound represented by the general formula (1) has a high heatresistance due to rigidity of its structure while having a low molecularweight, as compared with a conventional resist underlayer film materialincluding a polymer formed by co-polymerizing a repeating unit ofacenaphthylene with a substituted or non-substituted repeating unithaving a hydroxy group, and therefore the compound can be used evenunder a high-temperature baking condition. In addition, the compoundrepresented by the general formula (1) has a low molecular weight and alow viscosity as compared with the above conventional resist underlayerfilm material and the like, and therefore even when being applied to asubstrate having a step (in particular, fine space, hole pattern and thelike), the compound can be easily filled uniformly in every part of thestep, and as a result, a material for forming an underlayer film forlithography, using the compound, can be improved in terms of embeddingproperties in an advantageous manner as compared with the aboveconventional resist underlayer film material and the like. In addition,the compound has a relatively high carbon concentration to therebyimpart also a high etching resistance.

Herein, the compound represented by the general formula (1) preferablyincludes a compound represented by the following formula (1a).

In the formula (1a), X, R¹, R², m, n, p, and q are the same as definedin the general formula (1).

In addition, the compound represented by the general formula (1a) morepreferably includes a compound represented by the following formula(1b).

In the formula (1b), X, R¹, n, p, and q are the same as defined in theformula (1), each R⁴ independently represents a linear, branched orcyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or ahydroxyl group, and each m⁴ is independently an integer of 0 to 2.

In addition, the compound represented by the general formula (1b) morepreferably includes a compound represented by the following formula(1c).

In the formula (1c), R¹, n, and q are the same as defined in the formula(1), and R⁴ and m⁴ are the same as defined in the formula (1b).

In addition, the compound represented by the general formula (1c) morepreferably includes a compound represented by the following formula(1d).

In the formula (1d), R¹ represents a single bond or a divalenthydrocarbon group having 1 to 30 carbon atoms, the hydrocarbon group mayhave a cyclic hydrocarbon group, a double bond, a hetero atom or anaromatic group having 6 to 30 carbon atoms, q is the same as defined inthe formula (1), and R⁴ and m⁴ are the same as defined in the formula(1b).

In addition, the compound represented by the general formula (1d) morepreferably includes a compound represented by the following formula(1e).

In the formula (1e), R¹ is the same as defined in the formula (1d), q isthe same as defined in the formula (1), and R⁴ and m⁴ are the same asdefined in the formula (1b).

In the present embodiment, the compound having the structure representedby the general formula (1) preferably has a xanthene backbone or athioxanthene backbone represented by the following general formula (1A).When the compound has a xanthene backbone or a thioxanthene backbone,the compound tends to exhibit a higher heat resistance due to itsrigidity of the structure.

In the formula (1A), X represents an oxygen atom or a sulfur atom (whenX is an oxygen atom, the formula (1A) represents xanthene, and when X isa sulfur atom, the formula (1A) represents thioxanthene.).

In the present embodiment, the compound having the structure representedby the general formula (1) preferably has a benzoxanthene backbone or abenzothioxanthene backbone.

The compound represented by the general formula (1e) more preferablyincludes a compound represented by the following formula (1f) or (1g).

In the formula (1f) or (1g), R¹ is the same as defined in the formula(1d), q is the same as defined in the formula (1), and R⁴ and m⁴ are thesame as defined in the formula (1b).

In addition, the compound represented by the general formula (1f) ismore preferably a compound represented by the following formula (1h) or(1i).

In the formula (1h) or (1i), R¹ is the same as defined in the formula(1d), and R⁴ and m⁴ are the same as defined in the formula (1b).

In addition, the compound represented by the general formula (1g) morepreferably includes a compound represented by the following formula (1j)or (1k).

In the formula (1j) or (1k), R¹ is the same as defined in the formula(1d), and R⁴ and m⁴ are the same as defined in the formula (1b).

Examples of the compound represented by the formula (1) (where n=1, 2,or 3) include the following, but are not limited thereto.

The compound represented by the general formula (1) can be appropriatelysynthesized by applying a known method, and a synthesis method thereofis not particularly limited. For example, phenols, thiophenols,naphthols or thionaphthols, and aldehydes or ketones corresponding tothe structure of a desired compound can be subjected to apolycondensation reaction under ordinary pressure in the presence of anacid catalyst to thereby provide the compound represented by the generalformula (1). The reaction can also be performed under pressure, ifnecessary.

Examples of the phenols include phenol, methylphenol, methoxybenzene,catechol, resorcinol, hydroquinone, and trimethylhydroquinone, but arenot particularly limited thereto. These can be used alone, or two ormore thereof can be used in combination. Among them, hydroquinone ortrimethylhydroquinone is more preferably used from the viewpoint ofbeing capable of easily making a xanthene structure.

Examples of the thiophenols include benzenethiol, methylbenzenethiol,methoxybenzenethiol, benzenedithiol, and trimethylbenzenedithiol, butare not particularly limited thereto. These can be used alone, or two ormore thereof can be used in combination. Among them, benzenedithiol ortrimethylbenzenedithiol is more preferably used from the viewpoint ofbeing capable of easily making a thioxanthene structure.

Examples of the naphthols include naphthol, methylnaphthol,methoxynaphthalene, naphthalenediol, and naphthalenetriol, but are notparticularly limited thereto. These can be used alone, or two or morethereof can be used in combination. Among them, naphthalenediol ornaphthalenetriol is more preferably used from the viewpoint of beingcapable of easily making a xanthene structure.

Examples of the thionaphthols include naphthalenethiol,methylnaphthalenethiol, methoxy naphthalenethiol, naphthalenedithiol,and naphthalenetrithiol, but are not particularly limited thereto. Thesecan be used alone, or two or more thereof can be used in combination.Among them, naphthalenedithiol or naphthalenetrithiol is more preferablyused from the viewpoint of being capable of easily making a thioxanthenestructure.

Examples of the aldehydes include formaldehyde, trioxane,paraformaldehyde, acetaldehyde, propylaldehyde, butylaldehyde,hexylaldehyde, decylaldehyde, undecylaldehyde, phenylacetaldehyde,phenylpropylaldehyde, furfural, benzaldehyde, hydroxybenzaldehyde,fluorobenzaldehyde, chlorobenzaldehyde, nitrobenzaldehyde,methylbenzaldehyde, dimethylbenzaldehyde, ethylbenzaldehyde,propylbenzaldehyde, butylbenzaldehyde, cyclohexylbenzaldehyde,biphenylaldehyde, naphthaldehyde, anthracenecarboxaldehyde,phenanthrenecarboxaldehyde, pyrenecarboxaldehyde, glyoxal,glutaraldehyde, phthalaldehyde, naphthalenedicarboxaldehyde,biphenyldicarboxaldehyde, anthracenedicarboxaldehyde,bis(diformylphenyl)methane, bis(diformylphenyl)propane, andbenzenetricarboxaldehyde, but are not particularly limited thereto.These can be used alone, or two or more thereof can be used incombination. Among them, benzaldehyde, hydroxybenzaldehyde,fluorobenzaldehyde, chlorobenzaldehyde, nitrobenzaldehyde,methylbenzaldehyde, dimethylbenzaldehyde, ethylbenzaldehyde,propylbenzaldehyde, butylbenzaldehyde, cyclohexylbenzaldehyde,biphenylaldehyde, naphthaldehyde, anthracenecarboxaldehyde,phenanthrenecarboxaldehyde, pyrenecarboxaldehyde, glyoxal,glutaraldehyde, phthalaldehyde, naphthalenedicarboxaldehyde,biphenyldicarboxaldehyde, anthracenedicarboxaldehyde,bis(diformylphenyl)methane, bis(diformylphenyl)propane, orbenzenetricarboxaldehyde is preferably used from the viewpoint ofimparting a high heat resistance.

Examples of the ketones include acetone, methyl ethyl ketone,cyclobutanone, cyclopentanone, cyclohexanone, norbornanone,tricyclohexanone, tricyclodecanone, adamantanone, fluorenone,benzofluorenone, acenaphthenequinone, acenaphthenone, and anthraquinone,but are not particularly limited thereto. These can be used alone, ortwo or more thereof can be used in combination. Among them,cyclopentanone, cyclohexanone, norbornanone, tricyclohexanone,tricyclodecanone, adamantanone, fluorenone, benzofluorenone,acenaphthenequinone, acenaphthenone, or anthraquinone is preferably usedfrom the viewpoint of imparting a high heat resistance.

The acid catalyst for use in the above reaction can be appropriatelyselected from known ones and used, and is not particularly limited. Suchan acid catalyst is an inorganic acid or an organic acid, as widelyknown. Specific examples of the acid catalyst include inorganic acidssuch as hydrochloric acid, sulfuric acid, phosphoric acid, hydrobromicacid, or hydrofluoric acid; organic acids such as oxalic acid, malonicacid, succinic acid, adipic acid, sebacic acid, citric acid, fumaricacid, maleic acid, formic acid, p-toluenesulfonic acid, methanesulfonicacid, trifluoroacetic acid, dichloroacetic acid, trichloroacetic acid,trifluoromethanesulfonic acid, benzenesulfonic acid, naphthalenesulfonicacid, or naphthalenedisulfonic acid; Lewis acids such as zinc chloride,aluminum chloride, iron chloride, or boron trifluoride; or solid acidssuch as tungstosilicic acid, tungstophosphoric acid, silicomolybdicacid, or phosphomolybdic acid, but are not particularly limited thereto.Among them, organic acids and solid acids are preferable in terms ofproduction, and hydrochloric acid or sulfuric acid is preferably used interms of production such as availability or handleability. Herein, theseacid catalysts can be used alone, or two or more thereof can be used incombination. In addition, the amount of the acid catalyst to be used canbe appropriately set depending on the types of raw materials to be usedand the catalyst to be used, reaction conditions, and the like, and isnot particularly limited, but the amount is preferably 0.01 to 100 partsby mass based on 100 parts by mass of reaction raw materials.

A reaction solvent may also be used during the above reaction. Thereaction solvent that can be used is not particularly limited and isappropriately selected from known ones as long as the reaction of thealdehydes or ketones to be used and the phenols or thiophenols to beused progresses. Examples thereof include water, methanol, ethanol,propanol, butanol, tetrahydrofuran, dioxane, ethylene glycol dimethylether, ethylene glycol diethyl ether, or a mixed solvent thereof.Herein, these solvents can be used alone, or two or more thereof can beused in combination. In addition, the amount of the solvent to be usedcan be appropriately set depending on the types of raw materials to beused and the catalyst to be used, reaction conditions, and the like. Theamount of the solvent to be used is not particularly limited, butpreferably ranges from 0 to 2000 parts by mass based on 100 parts bymass of reaction raw materials. Furthermore, the reaction temperature inthe above reaction can be appropriately selected depending on thereactivity of reaction raw materials. The reaction temperature is notparticularly limited, but usually preferably ranges from 10 to 200° C.In order to form a xanthene structure or a thioxanthene structure as thecompound having the structure represented by general formula (1) of thepresent embodiment, the reaction temperature is preferably high and,specifically, preferably ranges from 60 to 200° C. Herein, the reactionmethod can be appropriately selected from known methods and used, and isnot particularly limited, but includes a method in which the phenols orthiophenols, the aldehydes or ketones, and the acid catalyst are chargedat once, and a method in which the phenols or thiophenols and thealdehydes or ketones are dropped in the presence of the acid catalyst.After completion of the polycondensation reaction, the resultingcompound can be isolated according to an ordinary method, and theisolation method is not particularly limited. For example, in order toremove the unreacted raw materials and the acid catalyst present in thesystem, a common method in which the temperature in a reaction tank israised to 130 to 230° C. to remove a volatile content at about 1 to 50mmHg can be adopted to thereby provide an objective compound.

The reaction progresses under such a preferable reaction condition that1 mol to an excess amount of the phenols or thiophenols and 0.001 to 1mol of the acid catalyst are used, based on 1 mol of the aldehydes orketones and are reacted at ordinary pressure and at 50 to 200° C. forabout 20 minutes to 100 hours.

After completion of the reaction, the objective compound can be isolatedby a known method. For example, the objective compound, the compoundhaving the structure represented by the general formula (1), can beobtained by concentrating a reaction liquid, adding pure water theretoto precipitate a reaction product, cooling the resultant to roomtemperature followed by filtration for separation, drying a solidobtained by filtration, then separating the solid into the reactionproduct and a by-product for purification by column chromatography, andperforming distilling off of the solvent, filtration and drying.

Herein, the molecular weight of the compound having the structurerepresented by the general formula (1) is not particularly limited, andthe weight average molecular weight (Mw) in terms of polystyrene ispreferably 500 to 30,000, more preferably 750 to 20,000. In addition,the compound having the structure represented by the general formula (1)preferably has a dispersity (weight average molecular weight Mw/numberaverage molecular weight Mn) in the range from 1.1 to 7 from theviewpoints of improving a crosslinking efficiency and suppressing avolatile component during baking. Herein, the Mw and the Mn can bemeasured by a method described in Examples described later.

The compound having the structure represented by the general formula (1)preferably has a high solubility in the solvent from the viewpoint ofmaking the application of a wet process easier. More specifically, whenthe solvent is 1-methoxy-2-propanol (PGME) and/or propylene glycolmonomethyl ether acetate (PGMEA), such a compound and/or resinpreferably have/has a solubility of 10% by mass or more in PGME orPGMEA. Herein, the solubility in PGME and/or PGMEA is defined as “Massof resin/(Mass of resin+Mass of solvent)×100 (% by mass)”. For example,in the case where 10 g of the compound represented by the generalformula (1) is dissolved in 90 g of PGMEA, the solubility of thecompound represented by the general formula (1) in PGMEA is evaluated asbeing “10% by mass or more”, and in the case where the compound is notdissolved, the solubility is evaluated as being “less than 10% by mass”.

In the case where the material for forming an underlayer film forlithography of the present embodiment contains an organic solvent thatis an optional component described later, the content of the compoundhaving the structure represented by the general formula (1) is notparticularly limited, but is preferably 1 to 33 parts by mass, morepreferably 2 to 25 parts by mass, further preferably 3 to 20 parts bymass, based on 100 parts by mass of the total amount of the componentsincluding the organic solvent.

(Other Component)

The material for forming an underlayer film for lithography according tothe present embodiment may contain, if necessary, other component suchas a crosslinking agent, an acid generating agent, and an organicsolvent, other than the compound having a structure represented by thegeneral formula (1). Hereinafter, these optional components will bedescribed.

The material for forming an underlayer film for lithography according tothe present embodiment may contain, if necessary, a crosslinking agentfrom the viewpoint of suppressing intermixing and the like.

Specific examples of the crosslinking agent usable in the presentembodiment include a melamine compound, a guanamine compound, aglycoluril compound, a urea compound, an epoxy compound, a thioepoxycompound, an isocyanate compound, an azide compound, and a compoundincluding a double bond such as an alkenyl ether group, these compoundshaving, as a substituent (crosslinkable group), at least one groupselected from a methylol group, an alkoxymethyl group, and anacyloxymethyl group, but are not particularly limited thereto. Herein,these crosslinking agents can be used alone, or two or more thereof canbe used in combination. Such a crosslinking agent may also be used as anadditive. Herein, such a crosslinkable group may also be introduced as apendant group into a polymer side chain in the compound represented bythe general formula (1). A compound including a hydroxy group can alsobe used as the crosslinking agent.

Specific examples of the melamine compound include, for example,hexamethylolmelamine, hexamethoxymethylmelamine, a compound in which 1to 6 methylol groups in hexamethylolmelamine are methoxymethylated, ormixtures thereof, and hexamethoxyethylmelamine,hexaacyloxymethylmelamine, a compound in which 1 to 6 methylol groups inhexamethylolmelamine are acyloxymethylated, or mixtures thereof.Specific examples of the epoxy compound include, for example,tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether,trimethylolpropane triglycidyl ether, and triethylolethane triglycidylether.

Specific examples of the guanamine compound include, for example,tetramethylolguanamine, tetramethoxymethylguanamine, a compound in which1 to 4 methylol groups in tetramethylolguanamine are methoxymethylated,or mixtures thereof, and tetramethoxyethylguanamine,tetraacyloxyguanamine, a compound in which 1 to 4 methylol groups intetramethylolguanamine are acyloxymethylated, or mixtures thereof.Specific examples of the glycoluril compound include, for example,tetramethylolglycoluril, tetramethoxyglycoluril,tetramethoxymethylglycoluril, a compound in which 1 to 4 methylol groupsin tetramethylolglycoluril are methoxymethylated, or mixtures thereof,and a compound in which 1 to 4 methylol groups intetramethylolglycoluril are acyloxymethylated, or mixtures thereof.Specific examples of the urea compound include, for example,tetramethylolurea, tetramethoxymethylurea, a compound in which 1 to 4methylol groups in tetramethylolurea are methoxymethylated, or mixturesthereof, and tetramethoxyethylurea.

Specific examples of the compound including an alkenyl ether groupinclude, for example, ethylene glycol divinyl ether, triethylene glycoldivinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinylether, tetramethylene glycol divinyl ether, neopentyl glycol divinylether, trimethylolpropane trivinyl ether, hexanediol divinyl ether,1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether,pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitolpentavinyl ether, and trimethylolpropane trivinyl ether.

In the material for forming an underlayer film for lithography accordingto the present embodiment, the content of the crosslinking agent is notparticularly limited, but the content is preferably 5 to 50 parts bymass and more preferably 10 to 40 parts by mass, based on 100 parts bymass of the compound having a structure represented by the generalformula (1). The content is set within the above preferable range toresult in tendencies to suppress the occurrence of the mixing phenomenonwith the resist layer, and to result in tendencies to enhance anantireflective effect and improve film formability after crosslinking.

The material for forming an underlayer film for lithography of thepresent embodiment may also contain, if necessary, an acid generatingagent from the viewpoint of further promoting a crosslinking reaction byheat. As the acid generating agent, one for generating an acid bypyrolysis and one for generating an acid by light irradiation are known,and any of them can be used.

The acid generating agent includes:

1) an onium salt of the following general formula (P1a-1), (P1a-2),(P1a-3) or (P1b),

2) a diazomethane derivative of the following general formula (P2),

3) a glyoxime derivative of the following general formula (P3),

4) a bissulfone derivative of the following general formula (P4),

5) a sulfonic acid ester of an N-hydroxyimide compound of the followinggeneral formula (P5),

6) a β-ketosulfonic acid derivative,

7) a disulfone derivative,

8) a nitrobenzylsulfonate derivative, and

9) a sulfonic acid ester derivative, but is not particularly limitedthereto. Herein, these acid generating agents can be used alone, or twoor more thereof can be used in combination.

(In the above formulae, each of R^(101a), R^(101b) and R^(101c)independently represents a linear, branched or cyclic alkyl group,alkenyl group, oxoalkyl group or oxoalkenyl group having 1 to 12 carbonatoms; an aryl group having 6 to 20 carbon atoms; or an aralkyl group oraryloxoalkyl group having 7 to 12 carbon atoms, and a part or all ofhydrogen atoms of these groups may be substituted with an alkoxy groupor the like. In addition, R^(101b) and R^(101c) may form a ring, and ifforming a ring, each of R^(101b) and R^(101c) independently representsan alkylene group having 1 to 6 carbon atoms. K⁻ represents anon-nucleophilic counter ion. R^(101d), R^(101e), R^(101f) and R^(101g)are represented by each independently adding a hydrogen atom toR^(101a), R^(101b) and R^(101c). R^(101d) and R^(101e), and R^(101d),R^(101e) and R^(101f) may form a ring, and if forming a ring, R^(101d)and R^(101e), and R^(101d), R^(101e) and R^(101f) represent an alkylenegroup having 3 to 10 carbon atoms, or a heteroaromatic ring havingtherein the nitrogen atom(s) in the formula.)

R^(101a), R^(101b), R^(101c), R^(101d), R^(101e), R^(101f) and R^(101g)described above may be the same or different from one another.Specifically, examples of the alkyl group include, but are not limitedto the following, a methyl group, an ethyl group, a propyl group, anisopropyl group, a n-butyl group, a sec-butyl group, a tert-butyl group,a pentyl group, a hexyl group, a heptyl group, an octyl group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopropylmethyl group, a 4-methyl cyclohexyl group, a cyclohexylmethylgroup, a norbornyl group, and an adamantyl group. Examples of thealkenyl group include, but are not limited to the following, a vinylgroup, an allyl group, a propenyl group, a butenyl group, a hexenylgroup, and a cyclohexenyl group. Examples of the oxoalkyl group include,but are not limited to the following, a 2-oxocyclopentyl group and a2-oxocyclohexyl group, and can include a 2-oxopropyl group, a2-cyclopentyl-2-oxoethyl group, a 2-cyclohexyl-2-oxoethyl group, and a2-(4-methylcyclohexyl)-2-oxoethyl group. Examples of the oxoalkenylgroup include, but are not limited to the following, a2-oxo-4-cyclohexenyl group and a 2-oxo-4-propenyl group. Examples of thearyl group include, but are not limited to the following, a phenylgroup, a naphthyl group, alkoxyphenyl groups such as a p-methoxyphenylgroup, a m-methoxyphenyl group, an o-methoxyphenyl group, anethoxyphenyl group, a p-tert-butoxyphenyl group, and am-tert-butoxyphenyl group; alkylphenyl groups such as a 2-methylphenylgroup, a 3-methylphenyl group, a 4-methylphenyl group, an ethylphenylgroup, a 4-tert-butylphenyl group, a 4-butylphenyl group, and adimethylphenyl group; alkylnaphthyl groups such as a methylnaphthylgroup and an ethylnaphthyl group; alkoxynaphthyl groups such as amethoxynaphthyl group and an ethoxynaphthyl group; dialkylnaphthylgroups such as a dimethylnaphthyl group and a diethylnaphthyl group; anddialkoxynaphthyl groups such as a dimethoxynaphthyl group and adiethoxynaphthyl group. Examples of the aralkyl group include, but arenot limited to the following, a benzyl group, a phenylethyl group, and aphenethyl group. Examples of the aryloxoalkyl group include, but are notlimited to the following, 2-aryl-2-oxoethyl groups such as a2-phenyl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a2-(2-naphthyl)-2-oxoethyl group. Examples of the non-nucleophiliccounter ion, K⁻, include, but are not limited to the following, halideions such as a chloride ion and a bromide ion; fluoroalkyl sulfonatessuch as triflate, 1,1,1-trifluoroethane sulfonate, and nonafluorobutanesulfonate; aryl sulfonates such as tosylate, benzene sulfonate,4-fluorobenzene sulfonate, and 1,2,3,4,5-pentafluorobenzene sulfonate;and alkyl sulfonates such as mesylate and butane sulfonate.

In the case where R^(101d), R^(101e), R^(101f) and R^(101g) are each aheteroaromatic ring having the nitrogen atom(s) in the formula, examplesof the heteroaromatic ring include imidazole derivatives (for example,imidazole, 4-methylimidazole, and 4-methyl-2-phenylimidazole), pyrazolederivatives, furazan derivatives, pyrroline derivatives (for example,pyrroline and 2-methyl-1-pyrroline), pyrrolidine derivatives (forexample, pyrrolidine, N-methylpyrrolidine, pyrrolidinone, andN-methylpyrrolidone), imidazoline derivatives, imidazolidinederivatives, pyridine derivatives (for example, pyridine,methylpyridine, ethylpyridine, propylpyridine, butylpyridine,4-(1-butylpentyl)pyridine, dimethylpyridine, trimethylpyridine,triethylpyridine, phenylpyridine, 3-methyl-2-phenylpyridine,4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine,butoxypyridine, dimethoxypyridine, 1-methyl-2-pyridone,4-pyrrolidinopyridine, 1-methyl-4-phenylpyridine,2-(1-ethylpropyl)pyridine, aminopyridine, and dimethylaminopyridine),pyridazine derivatives, pyrimidine derivatives, pyrazine derivatives,pyrazoline derivatives, pyrazolidine derivatives, piperidinederivatives, piperazine derivatives, morpholine derivatives, indolederivatives, isoindole derivatives, 1H-indazole derivatives, indolinederivatives, quinoline derivatives (for example, quinoline and3-quinolinecarbonitrile), isoquinoline derivatives, cinnolinederivatives, quinazoline derivatives, quinoxaline derivatives,phthalazine derivatives, purine derivatives, pteridin derivatives,carbazole derivatives, phenanthridine derivatives, acridine derivatives,phenazine derivatives, 1,10-phenanthroline derivatives, adeninederivatives, adenosine derivatives, guanine derivatives, guanosinederivatives, uracil derivative, and uridine derivatives.

The onium salts of the general formula (P1a-1) and the general formula(P1a-2) serve as a photo acid generating agent and a thermal acidgenerating agent. The onium salt of the general formula (P1a-3) servesas a thermal acid generating agent.

(In the formula (P1b), each of R^(102a) and R^(102b) independentlyrepresents a linear, branched or cyclic alkyl group having 1 to 8 carbonatoms. R¹⁰³ represents a linear, branched or cyclic alkylene grouphaving 1 to 10 carbon atoms. Each of R^(104a) and R^(104b) independentlyrepresents a 2-oxoalkyl group having 3 to 7 carbon atoms. K⁻ representsa non-nucleophilic counter ion.)

Specific examples of R^(102a) and R^(102b) include, but are not limitedto the following, a methyl group, an ethyl group, a propyl group, anisopropyl group, a n-butyl group, a sec-butyl group, a tert-butyl group,a pentyl group, a hexyl group, a heptyl group, an octyl group, acyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a4-methyl cyclohexyl group, and a cyclohexylmethyl group. Specificexamples of R¹⁰³ include, but are not limited to the following, amethylene group, an ethylene group, a propylene group, a butylene group,a pentylene group, a hexylene group, a heptylene group, an octylenegroup, a nonylene group, a 1,4-cyclohexylene group, a 1,2-cyclohexylenegroup, a 1,3-cyclopentylene group, a 1,4-cyclooctylene group, and a1,4-cyclohexanedimethylene group. Specific examples of R^(104a) andR^(104b) include, but are not limited to the following, a 2-oxopropylgroup, a 2-oxocyclopentyl group, a 2-oxocyclohexyl group, and a2-oxocycloheptyl group. K⁻ includes the same as those described in theformula (P1a-1), (P1a-2) and (P1a-3).

(In the formula (P2), each of R¹⁰⁵ and R¹⁰⁶ independently represents alinear, branched or cyclic alkyl group or halogenated alkyl group having1 to 12 carbon atoms, an aryl group or halogenated aryl group having 6to 20 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms.)

Examples of the alkyl group in each of R¹⁰⁵ and R¹⁰⁶ include, but arenot limited to the following, a methyl group, an ethyl group, a propylgroup, an isopropyl group, a n-butyl group, a sec-butyl group, atert-butyl group, a pentyl group, a hexyl group, a heptyl group, anoctyl group, an amyl group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a norbornyl group, and an adamantyl group. Examplesof the halogenated alkyl group include, but are not limited to thefollowing, a trifluoromethyl group, a 1,1,1-trifluoroethyl group, a1,1,1-trichloroethyl group, and a nonafluorobutyl group. Examples of thearyl group include, but are not limited to the following, alkoxyphenylgroups such as a phenyl group, a p-methoxyphenyl group, am-methoxyphenyl group, an o-methoxyphenyl group, an ethoxyphenyl group,a p-tert-butoxyphenyl group, and a m-tert-butoxyphenyl group; andalkylphenyl groups such as a 2-methylphenyl group, a 3-methylphenylgroup, a 4-methylphenyl group, an ethylphenyl group, a4-tert-butylphenyl group, a 4-butylphenyl group, and a dimethylphenylgroup. Examples of the halogenated aryl group include, but are notlimited to the following, a fluorophenyl group, a chlorophenyl group,and a 1,2,3,4,5-pentafluorophenyl group. Examples of the aralkyl groupinclude, but are not limited to the following, a benzyl group and aphenethyl group.

(In the formula (P3), each of R¹⁰⁷, R¹⁰⁸ and R¹⁰⁹ independentlyrepresents a linear, branched or cyclic alkyl group or halogenated alkylgroup having 1 to 12 carbon atoms; an aryl group or halogenated arylgroup having 6 to 20 carbon atoms; or an aralkyl group having 7 to 12carbon atoms. R¹⁰⁸ and R¹⁰⁹ may be bonded with each other to form acyclic structure, and if forming a cyclic structure, each of R¹⁰⁸ andR¹⁰⁹ represents a linear or branched alkylene group having 1 to 6 carbonatoms.)

The alkyl group, halogenated alkyl group, aryl group, halogenated arylgroup, and aralkyl group in each of R¹⁰⁷, R¹⁰⁸ and R¹⁰⁹ include the sameas those described in R¹⁰⁵ and R¹⁰⁶. Herein, examples of the alkylenegroup in each of R¹⁰⁸ and R¹⁰⁹ include, but are not limited to thefollowing, a methylene group, an ethylene group, a propylene group, abutylene group, and a hexylene group.

(In the formula (P4), R^(101a) and R^(101b) are the same as thosedescribed above.)

(In the formula (P5), R¹¹⁰ represents an arylene group having 6 to 10carbon atoms, an alkylene group having 1 to 6 carbon atoms, or analkenylene group having 2 to 6 carbon atoms. A part or all of hydrogenatoms of these groups may be further substituted with a linear orbranched alkyl group or alkoxy group having 1 to 4 carbon atoms, a nitrogroup, an acetyl group, or a phenyl group. R¹¹¹ represents a linear,branched or substituted alkyl group, alkenyl group or alkoxyalkyl grouphaving 1 to 8 carbon atoms, a phenyl group, or a naphthyl group. A partor all of hydrogen atoms of these groups may be further substituted withan alkyl group or alkoxy group having 1 to 4 carbon atoms; a phenylgroup that may be substituted with an alkyl group or alkoxy group having1 to 4 carbon atoms, a nitro group, or an acetyl group; a heteroaromaticgroup having 3 to 5 carbon atoms; or a chlorine atom or a fluorineatom.)

Herein, examples of the arylene group in R¹¹⁰ include, but are notlimited to the following, a 1,2-phenylene group and a 1,8-naphthylenegroup. Examples of the alkylene group include, but are not limited tothe following, a methylene group, an ethylene group, a trimethylenegroup, a tetramethylene group, a phenylethylene group, and anorbornane-2,3-diyl group. Examples of the alkenylene group include, butare not limited to the following, a 1,2-vinylene group, a1-phenyl-1,2-vinylene group, and a 5-norbornene-2,3-diyl group. Thealkyl group in R¹¹¹ includes the same as those in R^(101a) to R^(101c).Examples of the alkenyl group include, but are not limited to thefollowing, a vinyl group, a 1-propenyl group, an allyl group, a1-butenyl group, a 3-butenyl group, an isoprenyl group, a 1-pentenylgroup, a 3-pentenyl group, a 4-pentenyl group, a dimethylallyl group, a1-hexenyl group, a 3-hexenyl group, a 5-hexenyl group, a 1-heptenylgroup, a 3-heptenyl group, a 6-heptenyl group, and a 7-octenyl group.Examples of the alkoxyalkyl group include, but are not limited to thefollowing, a methoxymethyl group, an ethoxymethyl group, a propoxymethylgroup, a butoxymethyl group, a pentyloxymethyl group, a hexyloxymethylgroup, a heptyloxymethyl group, a methoxyethyl group, an ethoxyethylgroup, a propoxyethyl group, a butoxyethyl group, a pentyloxyethylgroup, a hexyloxyethyl group, a methoxypropyl group, an ethoxypropylgroup, a propoxypropyl group, a butoxypropyl group, a methoxybutylgroup, an ethoxybutyl group, a propoxybutyl group, a methoxypentylgroup, an ethoxypentyl group, a methoxyhexyl group, and a methoxyheptylgroup.

Herein, examples of the alkyl group having 1 to 4 carbon atoms, whichmay be further substituted, include, but are not limited to thefollowing, a methyl group, an ethyl group, a propyl group, an isopropylgroup, a n-butyl group, a an isobutyl group, and a tert-butyl group.Examples of the alkoxy group having 1 to 4 carbon atoms include, but arenot limited to the following, a methoxy group, an ethoxy group, apropoxy group, an isopropoxy group, a n-butoxy group, an isobutoxygroup, and tert-butoxy group. Examples of the phenyl group that may besubstituted with an alkyl group or alkoxy group having 1 to 4 carbonatoms, a nitro group, or an acetyl group include, but are not limited tothe following, a phenyl group, a tolyl group, a p-tert-butoxyphenylgroup, a p-acetylphenyl group, and a p-nitrophenyl group. Examples ofthe heteroaromatic group having 3 to 5 carbon atoms include, but are notlimited to the following, a pyridyl group and a furyl group.

Specific examples of acid generating agent include, but are not limitedto the following, onium salts such as tetramethylammoniumtrifluoromethanesulfonate, tetramethylammoniumnonafluorobutanesulfonate, triethylammonium nonafluorobutanesulfonate,pyridinium nonafluorobutanesulfonate, triethylammonium camphorsulfonate,pyridinium camphorsulfonate, tetra n-butylammoniumnonafluorobutanesulfonate, tetraphenylammoniumnonafluorobutanesulfonate, tetramethylammonium p-toluenesulfonate,diphenyliodonium trifluoromethanesulfonate,(p-tert-butoxyphenyl)phenyliodonium trifluoromethanesulfonate,diphenyliodonium p-toluenesulfonate, (p-tert-butoxyphenyl)phenyliodoniump-toluenesulfonate, triphenylsulfonium trifluoromethanesulfonate,(p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate,bis(p-tert-butoxyphenyl)phenylsulfonium trifluoromethanesulfonate,tris(p-tert-butoxyphenyl)sulfonium trifluoromethanesulfonate,triphenylsulfonium p-toluenesulfonate,(p-tert-butoxyphenyl)diphenylsulfonium p-toluenesulfonate,bis(p-tert-butoxyphenyl)phenylsulfonium p-toluenesulfonate,tris(p-tert-butoxyphenyl)sulfonium p-toluenesulfonate,triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfoniumbutanesulfonate, trimethylsulfonium trifluoromethanesulfonate,trimethylsulfonium p-toluenesulfonate,cyclohexylmethyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate,cyclohexylmethyl(2-oxocyclohexyl)sulfonium p-toluenesulfonate,dimethylphenylsulfonium trifluoromethanesulfonate,dimethylphenylsulfonium p-toluenesulfonate, dicyclohexylphenylsulfoniumtrifluoromethanesulfonate, dicyclohexylphenylsulfoniump-toluenesulfonate, trinaphthylsulfonium trifluoromethanesulfonate,cyclohexylmethyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate,(2-norbornyl)methyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate,ethylene bis[methyl(2-oxocyclopentyl)sulfoniumtrifluoromethanesulfonate], and1,2′-naphthylcarbonylmethyltetrahydrothiophenium triflate; diazomethanederivatives such as bis(benzenesulfonyl)diazomethane,bis(p-toluenesulfonyl)diazomethane, bis(xylenesulfonyl)diazomethane,bis(cyclohexylsulfonyl)diazomethane,bis(cyclopentylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane,bis(isobutylsulfonyl)diazomethane, bis(sec-butylsulfonyl)diazomethane,bis(n-propylsulfonyl)diazomethane, bis(isopropylsulfonyl)diazomethane,bis(tert-butylsulfonyl)diazomethane, bis(n-amylsulfonyl)diazomethane,bis(isoamylsulfonyl)diazomethane, bis(sec-amylsulfonyl)diazomethane,bis(tert-amylsulfonyl)diazomethane,1-cyclohexylsulfonyl-1-(tert-butylsulfonyl)diazomethane,1-cyclohexylsulfonyl-1-(tert-amylsulfonyl)diazomethane, and1-tert-amylsulfonyl-1-(tert-butylsulfonyl)diazomethane; glyoximederivatives such as bis-(p-toluenesulfonyl)-α-dimethylglyoxime,bis-(p-toluesulfonyl)-α-diphenylglyoxime,bis-(p-toluenesulfonyl)-α-dicyclohexylglyoxime,bis-(p-toluenesulfonyl)-2,3-pentanedioneglyoxime,bis-(p-toluenesulfonyl)-2-methyl-3,4-pentanedioneglyoxime,bis-(n-butanesulfonyl)-α-dimethylglyoxime,bis-(n-butanesulfonyl)-α-diphenylglyoxime,bis-(n-butanesulfonyl)-α-dicyclohexylglyoxime,bis-(n-butanesulfonyl)-2,3-pentanedioneglyoxime,bis-(n-butanesulfonyl)-2-methyl-3,4-pentanedioneglyoxime,bis-(methanesulfonyl)-α-dimethylglyoxime,bis-(trifluoromethanesulfonyl)-α-dimethylglyoxime,bis-(1,1,1-trifluoroethanesulfonyl)-α-dimethylglyoxime,bis-(tert-butanesulfonyl)-α-dimethylglyoxime,bis-(perfluorooctanesulfonyl)-α-dimethylglyoxime,bis-(cyclohexanesulfonyl)-α-dimethylglyoxime,bis-(benzenesulfonyl)-α-dimethylglyoxime,bis-(p-fluorobenzenesulfonyl)-α-dimethylglyoxime,bis-(p-tert-butylbenzenesulfonyl)-α-dimethylglyoxime,bis-(xylenesulfonyl)-α-dimethylglyoxime, andbis-(camphorsulfonyl)-α-dimethylglyoxime; bissulfone derivatives, suchas bisnaphthylsulfonylmethane, bistrifluoromethylsulfonylmethane,bismethylsulfonylmethane, bisethylsulfonylmethane,bispropylsulfonylmethane, bisisopropylsulfonylmethane,bis-p-toluenesulfonylmethane, and bisbenzenesulfonylmethane;β-ketosulfone derivatives such as2-cyclohexylcarbonyl-2-(p-toluenesulfonyl)propane and2-isopropylcarbonyl-2-(p-toluenesulfonyl)propane; disulfone derivativessuch as a diphenyldisulfone derivative and a dicyclohexyldisulfonederivative; nitrobenzylsulfonate derivatives such as 2,6-dinitrobenzylp-toluenesulfonate and 2,4-dinitrobenzyl p-toluenesulfonate; sulfonicacid ester derivatives such as 1,2,3-tris(methanesulfonyloxy)benzene,1,2,3-tris(trifluoromethanesulfonyloxy)benzene, and1,2,3-tris(p-toluenesulfonyloxy)benzene; and sulfonic acid esterderivatives of a N-hydroxyimide compound, such as N-hydroxysuccinimidemethanesulfonic acid ester, N-hydroxysuccinimidetrifluoromethanesulfonic acid ester, N-hydroxysuccinimide ethanesulfonicacid ester, N-hydroxysuccinimide 1-propanesulfonic acid ester,N-hydroxysuccinimide 2-propanesulfonic acid ester, N-hydroxysuccinimide1-pentanesulfonic acid ester, N-hydroxysuccinimide 1-octanesulfonic acidester, N-hydroxysuccinimide p-toluenesulfonic acid ester,N-hydroxysuccinimide p-methoxybenzenesulfonic acid ester,N-hydroxysuccinimide 2-chloroethanesulfonic acid ester,N-hydroxysuccinimide benzenesulfonic acid ester,N-hydroxysuccinimide-2,4,6-trimethylbenzenesulfonic acid ester,N-hydroxysuccinimide 1-naphthalenesulfonic acid ester,N-hydroxysuccinimide 2-naphthalenesulfonic acid ester,N-hydroxy-2-phenylsuccinimide methanesulfonic acid ester,N-hydroxymaleimide methanesulfonic acid ester, N-hydroxymaleimideethanesulfonic acid ester, N-hydroxy-2-phenylmaleimide methanesulfonicacid ester, N-hydroxyglutarimide methanesulfonic acid ester,N-hydroxyglutarimide benzenesulfonic acid ester, N-hydroxyphthalimidemethanesulfonic acid ester, N-hydroxyphthalimide benzenesulfonic acidester, N-hydroxyphthalimide trifluoromethanesulfonic acid ester,N-hydroxyphthalimide p-toluenesulfonic acid ester,N-hydroxynaphthalimide methanesulfonic acid ester,N-hydroxynaphthalimide benzenesulfonic acid ester,N-hydroxy-5-norbornene-2,3-dicarboxyimide methanesulfonic acid ester,N-hydroxy-5-norbornene-2,3-dicarboxyimide trifluoromethanesulfonic acidester, and N-hydroxy-5-norbornene-2,3-dicarboxyimide p-toluenesulfonicacid ester.

Among them, in particular, onium salts such as triphenylsulfoniumtrifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfoniumtrifluoromethanesulfonate, tris(p-tert-butoxyphenyl)sulfoniumtrifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate,(p-tert-butoxyphenyl)diphenylsulfonium p-toluenesulfonate,tris(p-tert-butoxyphenyl)sulfonium p-toluenesulfonate,trinaphthylsulfonium trifluoromethanesulfonate,cyclohexylmethyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate,(2-norbornyl)methyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate,and 1,2′-naphthylcarbonylmethyltetrahydrothiophenium triflate;diazomethane derivatives such as bis(benzenesulfonyl)diazomethane,bis(p-toluenesulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane,bis(n-butylsulfonyl)diazomethane, bis(isobutylsulfonyl)diazomethane,bis(sec-butylsulfonyl)diazomethane, bis(n-propylsulfonyl)diazomethane,bis(isopropylsulfonyl)diazomethane, andbis(tert-butylsulfonyl)diazomethane; glyoxime derivatives such asbis-(p-toluenesulfonyl)-α-dimethylglyoxime andbis-(n-butanesulfonyl)-α-dimethylglyoxime; bissulfone derivatives suchas bisnaphthylsulfonylmethane; and sulfonic acid ester derivatives of anN-hydroxyimide compound, such as N-hydroxysuccinimide methanesulfonicacid ester, N-hydroxysuccinimide trifluoromethanesulfonic acid ester,N-hydroxysuccinimide 1-propanesulfonic acid ester, N-hydroxysuccinimide2-propanesulfonic acid ester, N-hydroxysuccinimide 1-pentanesulfonicacid ester, N-hydroxysuccinimide p-toluenesulfonic acid ester,N-hydroxynaphthalimide methanesulfonic acid ester, andN-hydroxynaphthalimide benzenesulfonic acid ester are preferably used.

In the material for forming an underlayer film for lithography accordingto the present embodiment, the content of the acid generating agent isnot particularly limited, but the content is preferably 0.1 to 50 partsby mass and more preferably 0.5 to 40 parts by mass, based on 100 partsby mass of the compound having a structure represented by the generalformula (1). The content is set within the above range to result in atendency to increase the acid generation amount to promote acrosslinking reaction, and also to result in a tendency to suppress theoccurrence of the mixing phenomenon with a resist layer.

Furthermore, the material for forming an underlayer film for lithographyof the present embodiment may contain a basic compound from theviewpoint of improving preservation stability.

The basic compound serves as a quencher to an acid for preventing atrace amount of the acid generated from the acid generating agent frompromoting a crosslinking reaction. Examples of such a basic compoundinclude primary, secondary, and tertiary aliphatic amines, mixed amines,aromatic amines, heterocyclic amines, a nitrogen-containing compoundhaving a carboxy group, a nitrogen-containing compound having a sulfonylgroup, a nitrogen-containing compound having a hydroxyl group, anitrogen-containing compound having a hydroxyphenyl group, an alcoholicnitrogen-containing compound, an amide derivative, and an imidederivative, but are not particularly limited thereto.

Specific examples of the primary aliphatic amines include, but are notlimited to the following, ammonia, methylamine, ethylamine,n-propylamine, isopropylamine, n-butylamine, isobutylamine,sec-butylamine, tert-butylamine, pentylamine, tert-amylamine,cyclopentylamine, hexylamine, cyclohexylamine, heptylamine, octylamine,nonylamine, decylamine, dodecylamine, cetylamine, methylenediamine,ethylenediamine, and tetraethylenepentamine. Specific examples of thesecondary aliphatic amines include, but are not limited to thefollowing, dimethylamine, diethylamine, di-n-propylamine,diisopropylamine, di-n-butylamine, diisobutylamine, di-sec-butylamine,dipentylamine, dicyclopentylamine, dihexylamine, dicyclohexylamine,diheptylamine, dioctylamine, dinonylamine, didecylamine, didodecylamine,dicetylamine, N,N-dimethylmethylenediamine, N,N-dimethylethylenediamine,and N,N-dimethyltetraethylenepentamine. Specific examples of thetertiary aliphatic amines include, but are not limited to the following,trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine,tri-n-butylamine, triisobutylamine, tri-sec-butylamine, tripentylamine,tricyclopentylamine, trihexylamine, tricyclohexylamine, triheptylamine,trioctylamine, trinonylamine, tridecylamine, tridodecylamine,tricetylamine, N,N,N′,N′-tetramethylmethylenediamine,N,N,N′,N′-tetramethylethylenediamine, andN,N,N′,N′-tetramethyltetraethylenepentamine.

Specific examples of the mixed amines include, but are not limited tothe following, dimethylethylamine, methylethylpropylamine, benzylamine,phenethylamine, and benzyldimethylamine. Specific examples of thearomatic amines and heterocyclic amines include, but are not limited tothe following, aniline derivatives (for example, aniline,N-methylaniline, N-ethylaniline, N-propylaniline, N,N-dimethylaniline,2-methylaniline, 3-methylaniline, 4-methylaniline, ethylaniline,propylaniline, trimethylaniline, 2-nitroaniline, 3-nitroaniline,4-nitroaniline, 2,4-dinitroaniline, 2,6-dinitroaniline,3,5-dinitroaniline, and N,N-dimethyltoluidine), diphenyl(p-tolyl)amine,methyldiphenylamine, triphenylamine, phenylenediamine, naphthylamine,diaminonaphthalene, pyrrole derivatives (for example, pyrrole,2H-pyrrole, 1-methylpyrrole, 2,4-dimethylpyrrole, 2,5-dimethylpyrrole,and N-methylpyrrole), oxazole derivatives (for example, oxazole andisoxazole), thiazole derivatives (for example, thiazole andisothiazole), imidazole derivatives (for example, imidazole,4-methylimidazole, and 4-methyl-2-phenylimidazole), pyrazolederivatives, furazan derivatives, pyrroline derivatives (for example,pyrroline and 2-methyl-1-pyrroline), pyrrolidine derivatives (forexample, pyrrolidine, N-methylpyrrolidine, pyrrolidinone, andN-methylpyrrolidone), imidazoline derivatives, imidazolidinederivatives, pyridine derivatives (for example, pyridine,methylpyridine, ethylpyridine, propylpyridine, butylpyridine,4-(1-butylpentyl)pyridine, dimethylpyridine, trimethylpyridine,triethylpyridine, phenylpyridine, 3-methyl-2-phenylpyridine,4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine,butoxypyridine, dimethoxypyridine, 1-methyl-2-pyridone,4-pyrrolidinopyridine, 1-methyl-4-phenylpyridine,2-(1-ethylpropyl)pyridine, aminopyridine, and dimethylaminopyridine),pyridazine derivatives, pyrimidine derivatives, pyrazine derivatives,pyrazoline derivatives, pyrazolidine derivatives, piperidinederivatives, piperazine derivatives, morpholine derivatives, indolederivatives, isoindole derivatives, 1H-indazole derivatives, indolinederivatives, quinoline derivatives (for example, quinoline,3-quinolinecarbonitrile), isoquinoline derivatives, cinnolinederivatives, quinazoline derivatives, quinoxaline derivatives,phthalazine derivatives, purine derivatives, pteridin derivatives,carbazole derivatives, phenanthridine derivatives, acridine derivatives,phenazine derivatives, 1,10-phenanthroline derivatives, adeninederivatives, adenosine derivatives, guanine derivatives, guanosinederivatives, uracil derivatives, and uridine derivatives.

Furthermore, specific examples of the nitrogen-containing compoundhaving a carboxy group include, but are not limited to the following,aminobenzoic acid, indolecarboxylic acid, and amino acid derivatives(for example, nicotinic acid, alanine, arginine, aspartic acid, glutamicacid, glycine, histidine, isoleucine, glycylleucine, leucine,methionine, phenylalanine, threonine, lysine,3-aminopyrazine-2-carboxylic acid, and methoxyalanine). Specificexamples of the nitrogen-containing compound having a sulfonyl groupinclude 3-pyridinesulfonic acid and pyridinium p-toluenesulfonate.Specific examples of the nitrogen-containing compound having a hydroxylgroup, the nitrogen-containing compound having a hydroxyphenyl group,and the alcoholic nitrogen-containing compound include, but are notlimited to the following, 2-hydroxypyridine, aminocresol,2,4-quinolinediol, 3-indolemethanol hydrate, monoethanolamine,diethanolamine, triethanolamine, N-ethyldiethanolamine,N,N-diethylethanolamine, triisopropanolamine, 2,2′-iminodiethanol,2-aminoethanol, 3-amino-1-propanol, 4-amino-1-butanol,4-(2-hydroxyethyl)morpholine, 2-(2-hydroxyethyl)pyridine,1-(2-hydroxyethyl)piperazine, 1-[2-(2-hydroxyethoxyl)ethyl]piperazine,piperidine ethanol, 1-(2-hydroxyethyl)pyrrolidine,1-(2-hydroxyethyl)-2-pyrrolidone, 3-piperidino-1,2-propanediol,3-pyrrolidino-1,2-propanediol, 8-hydroxyjulolidine, 3-quinuclidinol,3-tropanol, 1-methyl-2-pyrrolidine ethanol, 1-aziridine ethanol,N-(2-hydroxyethyl)phthalimide, and N-(2-hydroxyethyl)isonicotinamide.Specific examples of the amide derivative include, but are not limitedto the following, formamide, N-methylformamide, N,N-dimethylformamide,acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, andbenzamide. Specific examples of the imide derivative include, but arenot limited to the following, phthalimide, succinimide, and maleimide.

In the material for forming an underlayer film for lithography of thepresent embodiment, the content of the basic compound is notparticularly limited, but is preferably 0.001 to 2 parts by mass, morepreferably 0.01 to 1 part by mass, based on 100 parts by mass of thecompound having the structure represented by the general formula (1).The content is set within the above preferable range to result in atendency to improve preservation stability without excessivelyinterrupting a crosslinking reaction.

In addition, the material for forming an underlayer film for lithographyof the present embodiment may contain other resins and/or compounds forthe purpose of imparting heat curability and controlling absorbance.Such other resins and/or compounds include naphthol resins, xyleneresins, naphthol-modified resins, phenol-modified resins of naphthaleneresins, polyhydroxystyrene, dicyclopentadiene resins, (meth)acrylate,dimethacrylate, trimethacrylate, tetramethacrylate, resins having anaphthalene ring such as vinylnaphthalene and polyacenaphthylene, resinshaving a biphenyl ring such as phenanthrenequinone and fluorene, resinshaving a heterocyclic ring having a hetero atom such as thiophene andindene, and resins not containing an aromatic ring; rosin-based resins,and resins or compounds including an alicyclic structure, such ascyclodextrin, adamantane(poly)ol, tricyclodecane(poly)ol and derivativesthereof, but are not particularly limited thereto. Furthermore, thematerial for forming an underlayer film for lithography of the presentembodiment may contain known additives. Examples of the known additivesinclude, but are not limited to the following, an ultraviolet absorber,a surfactant, a colorant, and a non-ionic surfactant.

The material for forming an underlayer film for lithography according tothe present embodiment may contain an organic solvent. As the organicsolvent, a known one can be appropriately used as long as it dissolvesat least the compound having a structure represented by the generalformula (1).

Specific examples of the organic solvent include, ketone-based solventssuch as acetone, methyl ethyl ketone, methyl isobutyl ketone, andcyclohexanone; cellosolve-based solvents such as propylene glycolmonomethyl ether and propylene glycol monomethyl ether acetate;ester-based solvents such as ethyl lactate, methyl acetate, ethylacetate, butyl acetate, isoamyl acetate, ethyl lactate, methylmethoxypropionate, and methyl hydroxyisobutyrate; alcohol-based solventssuch as methanol, ethanol, isopropanol, and 1-ethoxy-2-propanol; andaromatic hydrocarbons such as toluene, xylene, and anisole, but are notparticularly limited thereto. These organic solvents can be used alone,or two or more thereof can be used in combination.

Among the above organic solvents, particularly preferable arecyclohexanone, propylene glycol monomethyl ether, propylene glycolmonomethyl ether acetate, ethyl lactate, methyl hydroxyisobutyrate,anisole, in terms of safety.

The content of the organic solvent is not particularly limited, but itis preferably 100 to 10,000 parts by mass and more preferably 200 to5,000 parts by mass, based on 100 parts by mass of the compound having astructure represented by the general formula (1), from the viewpoint ofsolubility and film formability.

[Underlayer Film for Lithography and Forming Method of Multilayer ResistPattern]

An underlayer film for lithography of the present embodiment is formedfrom the material for forming an underlayer film for lithography of thepresent embodiment.

In addition, a forming method of a pattern of the present embodimentincludes step (A-1) of forming an underlayer film on a substrate byusing the material for forming an underlayer film for lithography of thepresent embodiment, step (A-2) of forming at least one photoresist layeron the underlayer film, and step (A-3) of irradiating a predeterminedregion of the photoresist layer with radiation and developing it with analkali, after step (A-2).

Furthermore, a forming method of a pattern of the present embodimentincludes step (B-1) of forming an underlayer film on a substrate byusing the material for forming an underlayer film for lithography of thepresent embodiment, step (B-2) of forming an intermediate layer film onthe underlayer film by using a silicon atom-containing resistintermediate layer film material, step (B-3) of forming at least onephotoresist layer on the intermediate layer film, step (B-4) ofirradiating a predetermined region of the photoresist layer withradiation and developing it with an alkali to form a resist pattern,after step (B-3), and step (B-5) of etching the intermediate layer filmwhile the resist pattern functions as a mask, etching the underlayerfilm while the obtained intermediate layer film pattern functions as anetching mask and etching the substrate while the obtained underlayerfilm pattern functions as an etching mask to form a pattern on thesubstrate, after step (B-4).

The underlayer film for lithography of the present embodiment is notparticularly limited in terms of the forming method thereof as long asit is formed from the material for forming an underlayer film forlithography of the present embodiment, and a known method can beapplied. For example, the underlayer film can be formed by applying thematerial for forming an underlayer film for lithography of the presentembodiment on the substrate by a known coating method or printing methodsuch as spin coating or screen printing, and removing an organic solventby volatilization or the like. The underlayer film is preferably bakedwhen being formed, in order to suppress the occurrence of the mixingphenomenon with an upperlayer resist and also promote a crosslinkingreaction. In this case, the baking temperature is not particularlylimited, but it is preferably within the range of 80 to 450° C., andmore preferably 200 to 400° C. In addition, the baking time is not alsoparticularly limited, but is preferably within the range of 10 to 300seconds. Herein, the thickness of the underlayer film can beappropriately selected depending on the required properties, and is notparticularly limited, but the thickness is usually preferably about 30to 20,000 nm and more preferably 50 to 15,000 nm. After the underlayerfilm is prepared, preferably, in the case of a two-layer process, asilicon-containing resist layer or a usual single-layer resist includinga hydrocarbon is prepared on the underlayer film, and in the case of athree-layer process, a silicon-containing intermediate layer is preparedon the underlayer film and a single-layer resist layer not containingsilicon is prepared on the silicon-containing intermediate layer. Inthese cases, a photoresist material for forming the resist layer, whichcan be used, is a known one.

After the underlayer film is prepared on the substrate, in the case of atwo-layer process, a silicon-containing resist layer or a usualsingle-layer resist including a hydrocarbon can be prepared on theunderlayer film, and in the case of a three-layer process, asilicon-containing intermediate layer can be prepared on the underlayerfilm, and a single-layer resist layer not containing silicon can beprepared on the silicon-containing intermediate layer. In these cases, aphotoresist material for forming the resist layer, which can be used, isappropriately selected from known ones, and is not particularly limited.

As the silicon-containing resist material for a two-layer process, apositive-type photoresist material is preferably used, which contains asilicon atom-containing polymer such as a polysilsesquioxane derivativeor a vinylsilane derivative used as a base polymer from the viewpoint ofoxygen gas-etching resistance, and an organic solvent, an acidgenerating agent and if necessary a basic compound. Herein, as thesilicon atom-containing polymer, a known polymer used in such a resistmaterial can be used.

As the silicon-containing intermediate layer for a three-layer process,a polysilsesquioxane-based intermediate layer is preferably used. Theintermediate layer tends to be allowed to have an effect as anantireflective film, thereby making it possible to effectively suppressreflection. For example, if a material including many aromatic groupsand having a high substrate-etching resistance is used for theunderlayer film in a 193 nm exposure process, a k-value tends to beincreased to increase substrate reflection, but the reflection can besuppressed by the intermediate layer to thereby make the substratereflection 0.5% or less. For the intermediate layer having such anantireflection effect, but are not limited to the following,polysilsesquioxane into which a phenyl group or a light-absorbing grouphaving a silicon-silicon bond for 193 nm exposure is introduced andwhich is to be crosslinked with an acid or heat is preferably used.

An intermediate layer formed by the Chemical Vapour Deposition (CVD)method can also be used. As the intermediate layer having a high effectas an antireflective film, prepared by the CVD method, but are notlimited to the following, for example, a SiON film is known. In general,the intermediate layer is formed by a wet process such as a spin coatingmethod or screen printing rather than the CVD method in terms ofsimplicity and cost effectiveness. Herein, the upperlayer resist in athree-layer process may be of positive-type or negative-type, and thesame one as a commonly used single-layer resist can be used therefor.

Furthermore, the underlayer film of the present embodiment can also beused as a usual antireflective film for use in a single-layer resist ora usual underlying material for suppressing pattern collapse. Theunderlayer film of the present embodiment can also be expected to serveas a hard mask for underlying processing because of being excellent inetching resistance for underlying processing.

In the case where a resist layer is formed by the photoresist material,a wet process such as a spin coating method or screen printing ispreferably used as in the case of forming the underlayer film. Theresist material is coated by a spin coating method or the like and thenusually pre-baked, and such pre-baking is preferably performed in therange of 80 to 180° C. for 10 to 300 seconds. Thereafter, in accordancewith an ordinary method, the resultant can be subjected to exposure,post-exposure bake (PEB), and development to obtain a resist pattern.Herein, the thickness of the resist film is not particularly limited,but generally, it is preferably 30 to 500 nm and more preferably 50 to400 nm.

Light for use in exposure may be appropriately selected depending on thephotoresist material to be used. In general, examples thereof includehigh energy radiation having a wavelength of 300 nm or less,specifically, excimer lasers of 248 nm, 193 nm, and 157 nm, a soft X-rayof 3 to 20 nm, electron beam, and an X-ray.

The resist pattern formed by the above method is a pattern whosecollapse is suppressed by the underlayer film of the present embodiment.Therefore, the underlayer film of the present embodiment can be used tothereby obtain a finer pattern, and an exposure amount necessary forobtaining such a resist pattern can be reduced.

Then, the obtained resist pattern is used as a mask to perform etching.As the etching of the underlayer film in a two-layer process, gasetching is preferably used. As the gas etching, etching using oxygen gasis suitable. In addition to oxygen gas, an inert gas such as He and Ar,and CO, CO₂, NH₃, SO₂, N₂, NO₂, and H₂ gases can also be added. The gasetching can also be performed not using oxygen gas but using only CO,CO₂, NH₃, N₂, NO₂, and H₂ gases. In particular, the latter gases arepreferably used for protecting a side wall for preventing a pattern sidewall from being undercut. On the other hand, also in the etching of theintermediate layer in a three-layer process, gas etching is preferablyused. As the gas etching, the same one as the one described in atwo-layer process can be applied. In particular, the intermediate layeris preferably processed in a three-layer process using a fluorocarbongas while the resist pattern functions as a mask. Thereafter, asdescribed above, the intermediate layer pattern is used as a mask toperform, for example, oxygen gas etching, thereby processing theunderlayer film.

Herein, in the case where an inorganic hard mask intermediate layer filmis formed as the intermediate layer, a silicon oxide film, a siliconnitride film, and a silicon oxynitride film (SiON film) are formed bythe CVD method, the ALD method, and the like. As the method for forminga nitride film, which is not limited to the following, the methoddescribed in, for example, Japanese Patent Laid-Open No. 2002-334869 andWO2004/066377 can be used.

While the photoresist film can be directly formed on such anintermediate layer film, an organic antireflective film (BARC) may alsobe formed on the intermediate layer film by spin coating, and thephotoresist film may also be formed thereon.

As the intermediate layer, a polysilsesquioxane-based intermediate layeris also preferably used. The resist intermediate layer film tends to beallowed to have an effect as an antireflective film, thereby making itpossible to effectively suppress reflection. As a specific material forthe polysilsesquioxane-based intermediate layer, which is not limited tothe following, one described in, for example, Japanese Patent Laid-OpenNo. 2007-226170 or Japanese Patent Laid-Open No. 2007-226204 can beused.

The next etching of the substrate can also be performed by an ordinarymethod, and, for example, when the substrate is made of SiO₂ or SiN,etching with mainly a fluorocarbon gas can be performed, and when thesubstrate is made of p-Si, Al, or W, etching mainly using achlorine-based gas or bromine-based gas can be performed. In the casewhere the substrate is processed by the etching with a fluorocarbon gas,the silicon-containing resist in a two-layer resist process and thesilicon-containing intermediate layer in a three-layer process arepeeled off at the same time as the processing of the substrate. On theother hand, in the case where the substrate is processed by the etchingwith a chlorine-based gas or bromine-based gas, the silicon-containingresist layer or the silicon-containing intermediate layer is peeled offseparately, and is generally peeled off by dry etching with afluorocarbon gas after the substrate is processed.

The underlayer film of the present embodiment is characterized by beingexcellent in etching resistance of such a substrate.

Herein, the substrate that can be used is appropriately selected fromknown ones, and is not particularly limited, but includes Si, α-Si,p-Si, SiO₂, SiN, SiON, W, TiN, and Al substrates. In addition, thesubstrate may also be a laminate having a processed film (processedsubstrate) on a base material (support). Such a processed film includesvarious Low-k films made of Si, SiO₂, SiON, SiN, p-Si, α-Si, W, W—Si,Al, Cu, and Al—Si, and stopper films thereof, and a material differentfrom the base material (support) is usually used therefor. Herein, thethickness of the substrate to be processed or the processed film is notparticularly limited, but it is usually preferably about 50 to 10,000 nmand more preferably 75 to 5,000 nm.

EXAMPLES

Hereinafter, the present invention will be described by SynthesisExamples and Examples in more detail, but the present invention is notlimited thereto at all.

(Carbon Concentration and Oxygen Concentration)

The carbon concentration and the oxygen concentration (% by mass) weremeasured by organic element analysis.

Apparatus: CHN CORDER MT-6 (manufactured by Yanaco Bunseki Kogyo Co.)

(Molecular Weight)

Measurement was performed by GC-MS analysis using Agilent 5975/6890Nmanufactured by Agilent.

Alternatively, measurement was performed by LC-MS analysis using AcquityUPLC/MALDI-Synapt HDMS manufactured by Water.

(Molecular Weight in Terms of Polystyrene)

Gel permeation chromatography (GPC) analysis was used to determine theweight average molecular weight (Mw) and the number average molecularweight (Mn) in terms of polystyrene, and to determine the degree ofdispersion (Mw/Mn).

Apparatus: Shodex GPC-101 type (manufactured by Showa Denko K. K.)

Column: KF-80M×3

Eluent: THF 1 ml/min

Temperature: 40° C.

(Pyrolysis Temperature (Tg))

An EXSTAR 6000 DSC apparatus manufactured by SII NanoTechnology Inc. wasused, and about 5 mg of a sample was placed in an unsealed aluminumcontainer and heated to 500° C. at a rate of temperature rise of 10°C./min in a nitrogen gas (30 ml/min) stream. In this time, a temperatureat which a reducing portion appeared on the base line was defined as apyrolysis temperature (Tg).

(Solubility)

The amount of each compound dissolved in 1-methoxy-2-propanol (PGME) andpropylene glycol monomethyl ether acetate (PGMEA) was measured at 23°C., and the results were evaluated according to the following criteria.

Evaluation A: 10% by weight or more

Evaluation B: 3% by weight or more and less than 10% by weight

Evaluation C: less than 3% by weight

Synthesis Examples 1 and 2 Synthesis of BisN-1 and BisN-2

A container having an inner volume of 100 ml, equipped with a stirrer, acondenser and a burette, was prepared. With the container were charged1.10 g (10 mmol) of 2,6-dihydroxynaphthalene (reagent produced bySigma-Aldrich Co., LLC.), 1.82 g (10 mmol) of 4-biphenylaldehyde(produced by Mitsubishi Gas Chemical Company, Inc.) and 30 ml of methylisobutyl ketone, and 5 ml of 95% sulfuric acid was added thereto toprepare a reaction liquid. This reaction liquid was stirred at 100° C.for 6 hours to perform a reaction. Then, the reaction liquid wasconcentrated, 50 g of pure water was added thereto to precipitate areaction product, and the resultant was cooled to room temperaturefollowed by filtration for separation. A solid obtained by filtrationwas dried, and thereafter separated and purified by columnchromatography to thereby provide each of 0.10 g of objective compound(BisN-1) and 0.05 g of objective compound (BisN-2) represented by thefollowing formulae.

Herein, the following peaks were observed by 400 MHz-¹H-NMR, and it wasconfirmed that the compound had a chemical structure of the followingformula.

Compound BisN-1

¹H-NMR: (d-DMSO, internal standard TMS)

δ (ppm) 9.6 (2H, O—H), 7.2-8.3 (32H, Ph-H), 6.6 (2H, C—H)

Compound BisN-2

¹H-NMR: (d-DMSO, internal standard TMS)

δ (ppm) 9.6 (2H, O—H), 7.2-8.4 (45H, Ph-H), 6.6 (3H, C—H)

As a result of organic element analysis, the carbon concentration andthe oxygen concentration of compound BisN-1 were 87.02% and 8.28%,respectively.

In addition, the carbon concentration and the oxygen concentration ofcompound BisN-2 were 87.92% and 7.41%, respectively. Compound BisN-1 andcompound BisN-2 had a high carbon content rate and a low oxygen contentrate, and thus were evaluated as having a high etching resistance.

The molecular weights of the resulting compounds were measured by theabove method, and as a result, the molecular weights of compound BisN-1and compound BisN-2 were 772 and 1078, respectively.

As a result of thermogravimetric measurement (TG), both of the pyrolysistemperatures of compound BisN-1 and compound BisN-2 were 400° C. orhigher. Therefore, compound BisN-1 and compound BisN-2 were evaluated ashaving a high heat resistance and also applicability to high-temperaturebaking.

The solubilities of compound BisN-1 and compound BisN-2 in PGME andPGMEA were 10% by weight or more (Evaluation A), and compound BisN-1 andcompound BisN-2 were evaluated as having an excellent solubility.Therefore, compound BisN-1 and compound BisN-2 were evaluated as havinga high preservation stability in a solution state and also a sufficientapplicability to an edge bead rinse liquid (mixed liquid of PGME/PGMEA)widely used in a semiconductor microfabrication process.

Production Example 1

A four-neck flask having a bottom outlet and an inner volume of 10 L,equipped with a Dimroth condenser, a thermometer and a stirring blade,was prepared. With this four-neck flask were charged 1.09 kg of1,5-dimethylnaphthalene (7 mol, produced by Mitsubishi Gas ChemicalCompany, Inc.), 2.1 kg of a 40% by mass aqueous formalin solution (28mol as formaldehyde, produced by Mitsubishi Gas Chemical Company, Inc.)and 0.97 ml of 98% by mass sulfuric acid (produced by Kanto ChemicalCo., Inc.) under a nitrogen stream, and allowed the reaction to rununder ordinary pressure with refluxing at 100° C. for 7 hours.Thereafter, 1.8 kg of ethylbenzene (special grade chemical, produced byWako Pure Chemical Industries, Ltd.) as a dilution solvent was added tothe reaction liquid and left to stand, and thereafter an aqueous phasebeing a bottom phase was removed. Furthermore, the resultant wasneutralized and washed with water, and ethylbenzene and the unreacted1,5-dimethylnaphthalene were distilled off under reduced pressure,thereby providing 1.25 kg of a dimethylnaphthalene formaldehyde resin asa light-brown solid.

With respect to the molecular weight of the resultingdimethylnaphthalene formaldehyde, Mn was 562, Mw was 1168 and Mw/Mn was2.08. In addition, the carbon concentration was 84.2% by mass, and theoxygen concentration was 8.3% by mass.

Subsequently, a four-neck flask having an inner volume of 0.5 L,equipped with a Dimroth condenser, a thermometer and a stirring blade,was prepared. With this four-neck flask were charged 100 g (0.51 mol) ofthe dimethylnaphthalene formaldehyde resin obtained as above and 0.05 gof p-toluenesulfonic acid under a nitrogen stream, and heated for 2hours with the temperature being raised to 190° C., and then stirred.Thereafter, 52.0 g (0.36 mol) of 1-naphthol was further added thereto,and further heated to 220° C. to allow the reaction to run for 2 hours.After being diluted with a solvent, the resultant was neutralized andwashed with water, and the solvent was removed under reduced pressure tothereby provide 126.1 g of a modified resin (CR-1) as a blackish brownsolid.

With respect to the resulting resin (CR-1), Mn was 885, Mw was 2220 andMw/Mn was 4.17. In addition, the carbon concentration was 89.1% by massand the oxygen concentration was 4.5% by mass.

Examples 1 to 2, Comparative Example 1

A material for forming an underlayer film for lithography in each ofExamples 1 to 2 and Comparative Example 1 was prepared so as to havecomposition shown in Table 1. That is, the following materials wereused.

Acid generating agent: di-tert-butyldiphenyliodoniumnonafluoromethanesulfonate (DTDPI) produced by Midori Kagaku Co., Ltd.

Crosslinking agent: Nikalac MX270 (Nikalac) produced by Sanwa ChemicalCo., Ltd.

Organic solvent: cyclohexanone (CHN)

Novolac: PSM4357 produced by Gunei Chemical Industry Co., Ltd.

Then, a silicon substrate was spin-coated with the material for formingan underlayer film in each of Examples 1 to 2 and Comparative Example 1,thereafter the resultant was baked at 240° C. for 60 seconds and furtherat 400° C. for 120 seconds to prepare each underlayer film having a filmthickness of 200 nm.

An etching test was performed under conditions shown below to evaluateetching resistance. The evaluation results are shown in Table 1.

[Etching Test]

Etching apparatus: RIE-10NR manufactured by Samco Inc.

Output: 50 W

Pressure: 20 Pa

Time: 2 min

Etching gas

Ar gas flow rate:CF₄ gas flow rate:O₂ gas flow rate=50:5:5 (sccm)

[Evaluation of Etching Resistance]

The evaluation of etching resistance was performed according to thefollowing procedure.

First, an underlayer film of novolac was prepared under the sameconditions as those in Example 1 except that novolac (PSM4357 producedby Gunei Chemical Industry Co., Ltd.) was used instead of the compound(BisN-1) of Example 1. Then, the underlayer film of novolac wassubjected to the etching test, and the etching rate in that time wasmeasured.

Then, the underlayer films of Examples 1 to 2 and Comparative Example 1were subjected to the etching test in the same manner, and the etchingrates here were measured.

Then, the etching resistances were evaluated according to the followingcriteria based on the etching rate of the underlayer film of novolac.

<Evaluation Criteria>

A: etching rate of less than −10% compared with the underlayer film ofnovolac

B: etching rate of −10% to +5% compared with underlayer film of novolac

C: etching rate of more than +5% compared with the underlayer film ofnovolac

TABLE 1 Acid Evalua- Compound Organic generating Crosslinking tion of orResin solvent agent agent etching (parts (parts (parts (parts resis- bymass) by mass) by mass) by mass) tance Example 1 BisN-1 CHN DTDPINikalac A (10) (90) (0.5) (0.5) Example 2 BisN-2 CHN DTDPI Nikalac A(10) (90) (0.5) (0.5) Compar- CR-1 CHN DTDPI Nikalac C ative (10) (90)(0.5) (0.5) Example 1

Examples 3 to 4

Then, the solution of the material for forming an underlayer film forlithography in each of Examples 1 to 2 was coated on a SiO₂ substratehaving a film thickness of 300 nm, and baked at 240° C. for 60 secondsand further at 400° C. for 120 seconds to thereby form an underlayerfilm having a film thickness of 80 nm. A resist solution for ArF wascoated on the underlayer film, and baked at 130° C. for 60 seconds tothereby form a photoresist layer having a film thickness of 150 nm.Herein, as the resist solution for ArF, one prepared by blending 5 partsby mass of the compound of the following formula (11), 1 part by mass oftriphenylsulfonium nonafluoromethanesulfonate, 2 parts by mass oftributylamine, and 92 parts by mass of PGMEA was used.

Herein, the compound represented by the following formula (11) wasprepared as follows. That is, 4.15 g of2-methyl-2-methacryloyloxyadamantane, 3.00 g ofmethacryloyloxy-γ-butyrolactone, 2.08 g of 3-hydroxy-1-adamantylmethacrylate and 0.38 g of azobisisobutyronitrile were dissolved in 80mL of tetrahydrofuran to provide a reaction solution. This reactionsolution was subjected to polymerization under a nitrogen atmosphere for22 hours with the reaction temperature being kept at 63° C., andthereafter the reaction solution was dropped in 400 mL of n-hexane. Theproduct resin thus obtained was solidified and purified, and a whitepowder produced was subjected to filtering and dried at 40° C. underreduced pressure overnight to provide the compound represented by thefollowing formula (11).

(in the formula (11), the numerals 40, 40, and 20 indicate theproportions of the respective constituent units, and do not mean a blockcopolymer.)

Then, the photoresist layer was exposed by using an electron beamlithography apparatus (ELS-7500, produced by Elionix, Inc., 50 keV),baked at 115° C. for 90 seconds (PEB), and developed with a 2.38% bymass aqueous tetramethylammonium hydroxide (TMAH) solution for 60seconds, thereby providing a positive-type resist pattern.

Comparative Example 2

Except that no underlayer film was formed, the same manner as in Example2 was performed to form a photoresist layer directly on a SiO₂substrate, to provide a positive-type resist pattern.

[Evaluation]

The shapes of the resist patterns of 55 nm L/S (1:1) and 80 nm L/S (1:1)provided in each of Examples 3 to 4 and Comparative Example 2 wereobserved using an electron microscope (S-4800) manufactured by HitachiLtd. With respect to the shape of the resist pattern after development,a shape having no pattern collapse and having a good rectangle propertywas evaluated as being good, and a shape not having such properties wasevaluated as being poor. In the observation results, the smallest linewidth in which no pattern collapse was observed and a good rectangleproperty was achieved was defined as an evaluation index of resolution.Furthermore, the smallest amount of electron beam energy in which a goodpattern shape could be drawn was defined as an evaluation index ofsensitivity. The results are shown in Table 2.

TABLE 2 Resist pattern Material for Resolu- Sensi- formation formingtion tivity after underlayer film (nmL/S) (μC/cm²) development Example 3Material described 55 12 Good in Table 1 (Example 1) Example 4 Materialdescribed 55 12 Good in Table 1 (Example 2) Compar- Not used 80 26 Poorative Example 2

As can be seen from Table 2, it was confirmed that the underlayer filmsof Examples 3 to 4 were significantly excellent in resolution andsensitivity as compared with Comparative Example 2. In addition, it wasconfirmed that the shape of the resist pattern after development alsohad no pattern collapse and a good rectangle property. Furthermore, itwas shown from the difference from the shape of the resist pattern afterdevelopment that the material for forming an underlayer film forlithography in each of Examples had good adhesiveness with a resistmaterial.

Examples 5 to 6

The solution of the material for forming an underlayer film forlithography in each of Examples 1 to 2 was coated on a SiO₂ substratehaving a film thickness of 300 nm, and baked at 240° C. for 60 secondsand further at 400° C. for 120 seconds to thereby form an underlayerfilm having a film thickness of 80 nm. This underlayer film was coatedwith a silicon-containing intermediate layer material. Then, theresultant was baked at 200° C. for 60 seconds to thereby form anintermediate layer film having a film thickness of 35 nm. Furthermore,the resist solution for ArF used in Example 3 to 4 was coated on theintermediate layer film, and baked at 130° C. for 60 seconds to therebyform a photoresist layer having a film thickness of 150 nm. Herein, asthe silicon-containing intermediate layer material, a siliconatom-containing polymer described in <Synthesis Example 1> in JapanesePatent Laid-Open No. 2007-226170 was used.

Then, the photoresist layer was exposed by using an electron beamlithography apparatus (ELS-7500, produced by Elionix, Inc., 50 keV),baked at 115° C. for 90 seconds (PEB), and developed with a 2.38% bymass aqueous tetramethylammonium hydroxide (TMAH) solution for 60seconds, thereby providing a positive-type resist pattern of 55 nmL/S(1:1).

Thereafter, the silicon-containing intermediate layer film (SOG) wassubjected to dry etching processing while the obtained resist patternfunctioned as a mask using RIE-10NR manufactured by Samco Inc.Subsequently, dry etching processing of the underlayer film while theobtained silicon-containing intermediate layer film pattern functionedas a mask and dry etching processing of the SiO₂ film while the obtainedunderlayer film pattern functioned as a mask were performed,sequentially.

The respective etching conditions are shown as follows.

Conditions of resist pattern etching on resist intermediate layer film

Output: 50 W

Pressure: 20 Pa

Time: 1 min

Etching gas

Ar gas flow rate:CF₄ gas flow rate:O₂ gas flow rate=50:8:2 (sccm)

Conditions of resist intermediate film pattern etching on resistunderlayer film

Output: 50 W

Pressure: 20 Pa

Time: 2 min

Etching gas

Ar gas flow rate:CF₄ gas flow rate:O₂ gas flow rate=50:5:5 (sccm)

Conditions of resist underlayer film pattern etching on SiO₂ film

Output: 50 W

Pressure: 20 Pa

Time: 2 min

Etching gas

Ar gas flow rate:C₅F₁₂ gas flow rate:C₂F₆ gas flow rate:O₂ gas flowrate=50:4:3:1 (sccm)

[Evaluation]

The cross section of the pattern (the shape of the SiO₂ film afteretching) of each of Examples 5 to 6 obtained as described above wasobserved using an electron microscope (S-4800) manufactured by HitachiLtd. As a result, it was confirmed that the shape of the SiO₂ film afteretching in multilayer resist processing was rectangular with no defectsobserved, and the cross section of the pattern also had a good shape ineach of Examples 5 to 6 using the underlayer film of the presentinvention.

As described above, the present invention is not limited to theembodiments and Examples, and can be appropriately modified withoutdeparting the gist thereof.

The present application is based on Japanese Patent Application(Japanese Patent Application No. 2013-023809) filed on Feb. 8, 2013, andthe content thereof is herein incorporated by reference.

The material for forming an underlayer film for lithography and theunderlayer film of the present invention have a relatively high carbonconcentration, a relatively low oxygen concentration, a relatively highheat resistance and also a relatively high solvent solubility, and whichcan be applied to a wet process. Therefore, the material for forming anunderlayer film for lithography and the underlayer film of the presentinvention can be widely and effectively utilized in various applicationsin which these properties are required. Therefore, the present inventioncan be widely and effectively utilized for, for example, an electricinsulating material; a resist resin; a sealing resin for asemiconductor; an adhesive for a printed wiring board; an electriclaminated board mounted on electrical equipment, electronic equipment,industrial equipment and the like; a matrix resin for a prepreg mountedon electrical equipment, electronic equipment, industrial equipment andthe like; a material for a build-up laminated board; a resin forfiber-reinforced plastics; a sealing resin for a liquid crystal displaypanel; a paint; various coating agents; an adhesive; a coating agent fora semiconductor; a resist resin for a semiconductor; and a resin forforming an underlayer film. In particular, the present invention can beparticularly effectively utilized in the field of an underlayer film forlithography and an underlayer film for a multilayer resist.

The invention claimed is:
 1. A material for forming an underlayer filmfor lithography, comprising a compound having a structure represented bythe following general formula (1):

in formula (1), each X independently represents an oxygen atom or asulfur atom, R¹ represents a single bond or a 2n-valent hydrocarbongroup having 1 to 30 carbon atoms, the hydrocarbon group may have acyclic hydrocarbon group, a double bond, a hetero atom or an aromaticgroup having 6 to 30 carbon atoms, each R² independently represents alinear, branched or cyclic alkyl group having 1 to 10 carbon atoms, anaryl group having 6 to 10 carbon atoms, an alkenyl group having 2 to 10carbon atoms, or a hydroxyl group, each m is independently an integer of0 to 3, n is 1, p is 0 or 1, and q is an integer of 1 to 100, whereinthe compound having the structure represented by the general formula (1)comprises a compound represented by the following general formula (1c):

in formula (1c), R¹, n, and q are the same as defined in the formula (1)and each R⁴ independantly represents a linear, branched or cyclic alkylgroup having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbonatoms, an alkenyl group having 2 to 10 carbon atoms, or a hydroxylgroup, and each m⁴ is independantly an integer of 0 to 2; and at leastone of an acid generating agent and a crosslinking agent.
 2. Thematerial for forming the underlayer film for lithography according toclaim 1, wherein the compound represented by the general formula (1c)comprises a compound represented by the following general formula (1e):

in formula (1e), R¹ is the same as defined in the formula (1d), q is thesame as defined in the formula (1), and R⁴ and m⁴ are the same asdefined in the formula (1c).
 3. The material for forming the underlayerfilm for lithography according to claim 2, wherein the compoundrepresented by the general formula (1e) comprises a compound representedby the following general formula (1f) or (1g):

in formula (1f), and formula (1g), R¹ is the same as defined in theformula (1d), q is the same as defined in the formula (1), and R⁴ and m⁴are the same as defined in the formula (1c).
 4. The material for formingthe underlayer film for lithography according to claim 3, wherein thecompound represented by the general formula (1f) comprises a compoundrepresented by the following general formula (1h) or (1i):

in formula (1h) and formula (1i), R¹ is the same as defined in theformula (1d), and R⁴ and m⁴ are the same as defined in the formula (1c).5. The material for forming the underlayer film for lithographyaccording to claim 4, wherein the compound represented by the generalformula (1h) comprises a compound represented by the following formula(BisN-1):


6. The material for forming the underlayer film for lithographyaccording to claim 4, wherein the compound represented by the generalformula (1i) comprises a compound represented by the following formula(BisN-2):


7. The material for forming the underlayer film for lithographyaccording to claim 3, wherein the compound represented by the generalformula (1g) comprises a compound represented by the following generalformula (1j) or (1k):

in formula (1j) and formula (1k), R¹ is the same as defined in theformula (1d), and R⁴ and m⁴ are the same as defined in the formula (1c).8. The material for forming the underlayer film for lithographyaccording to claim 1, further comprising an organic solvent.
 9. Thematerial for forming the underlayer film for lithography according toclaim 1, comprising the acid generating agent.
 10. The material forforming the underlayer film for lithography according to claim 1,comprising the crosslinking agent.
 11. An underlayer film forlithography, formed from the material for forming the underlayer filmfor lithography according to claim
 1. 12. A forming method of a pattern,comprising: step (A-1) of forming an underlayer film on a substrate byusing the material for forming the underlayer film according to claim 1;step (A-2) of forming at least one photoresist layer on the underlayerfilm; and step (A-3) of irradiating a predetermined region of thephotoresist layer with radiation followed by developing with an alkali,after step (A-2).
 13. A forming method of a pattern, comprising: step(B-1) of forming an underlayer film on a substrate by using the materialfor forming the underlayer film according to claim 1; step (B-2) offorming an intermediate layer film on the underlayer film by using asilicon atom-containing resist intermediate layer film material; step(B-3) of forming at least one photoresist layer on the intermediatelayer film; step (B-4) of irradiating a predetermined region of thephotoresist layer with radiation followed by developing with an alkalito form a resist pattern, after step (B-3); and step (B-5) of etchingthe intermediate layer film while the resist pattern functions as amask, etching the underlayer film while the obtained intermediate layerfilm pattern functions as an etching mask and etching the substratewhile the obtained underlayer film pattern functions as an etching maskto form a pattern on the substrate, after step (B-4).
 14. A compoundrepresented by the following formula (BisN-1):


15. A compound represented by the following formula (BisN-2):


16. A method for forming an underlayer film for lithography, the methodcomprising: forming the underlayer film by using a material for formingthe underlayer film for lithography comprising at least one of an acidgenerating agent and a crosslinking agent together with a compoundrepresented by the following formula (1):

wherein, each X independently represents an oxygen atom or a sulfuratom, R¹ represents a single bond or a 2n-valent hydrocarbon grouphaving 1 to 30 carbon atoms, the hydrocarbon group may have a cyclichydrocarbon group, a double bond, a hetero atom or an aromatic grouphaving 6 to 30 carbon atoms, each R² independently represents a linear,branched or cyclic alkyl group having 1 to 10 carbon atoms, an arylgroup having 6 to 10 carbon atoms, an alkenyl group having 2 to 10carbon atoms, or a hydroxyl group, m is an integer of 0 to 3, n is 1, pis 0 or 1, and q is an integer of 1 to 100, provided that each R² andeach m may be different, and wherein the compound having the structurerepresented by the general formula (1) comprises a compound representedby the following general formula (1c):

wherein, R¹, n, and q are the same as defined in the formula (1) andeach R⁴ independantly represents a linear, branched or cyclic alkylgroup having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbonatoms, an alkenyl group having 2 to 10 carbon atoms, or a hydroxylgroup, and each m⁴ is independantly an integer of 0 to 2.